Method of implanting a heart valve prosthesis

ABSTRACT

A method of implanting a percutaneous heart valve prosthesis via a catheter. The heart valve prosthesis includes a valve body frame made of a nickel-titanium alloy. The valve body frame is collapsible for fitting within the catheter. A flexible skirt is sutured to the valve body frame for blocking retrograde blood flow. A one-way valve is positioned within the valve body frame for permitting blood to flow from a first end of the valve body frame to a second end. The one-way valve is preferably formed by three flexible valve leaflets made from a pericardial material. A plurality of barbs is spaced about the periphery of the valve body frame. Each of the prongs points toward the first end of the valve body frame for preventing migration of the heart valve prosthesis towards an atrium of the heart.

CROSS REFERENCE TO RELATED APPLICATIONS

This application continuation of U.S. application Ser. No. 17/234,646,filed Apr. 19, 2021, which is a continuation of U.S. application Ser.No. 16/265,201, filed Feb. 1, 2019, now U.S. Pat. No. 10,993,806, whichis a continuation of U.S. application Ser. No. 14/623,301, filed Feb.16, 2015, now U.S. Pat. No. 10,213,298, which is a divisional of U.S.application Ser. No. 10/598,716, filed May 28, 2008, now U.S. Pat. No.8,979,922, which is the National Stage of International Application No.PCT/AU2005/000346, filed Mar. 11, 2005, which claims the benefit of U.S.Provisional Application No. 60/551,976, filed Mar. 11, 2004, the entiredisclosures of which are incorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a percutaneous heart valve prosthesis,and particularly relates to, but is not limited to, a percutaneousmitral valve prosthesis.

BACKGROUND OF THE INVENTION

Heart valve regurgitation is a condition whereby the heart valve doesnot seal completely as a result of disease or injury, and may have fatalconsequences.

Malfunctioning heart valves have typically been replaced with mechanicalor biologic heart valve prostheses using highly invasive open-heartsurgery techniques. Whilst there has been some success in developingreplacement aortic valve prostheses for delivery via percutaneouscatheter-based methods, these techniques have not been particularlysuccessful when applied to mitral valve prostheses.

Mitral valve replacement is firstly made difficult as a result of theanatomy of the mitral valve, and particularly that of the mitral valveannulus in which the mitral valve is leaflets are located. The mitralvalve annulus is typically very distorted, and of unpredictable andnon-uniform geometries, as compared to the relatively uniform aorticvalve annulus. This unpredictable anatomy makes it difficult to design apre-constructed mitral valve prosthesis that would fit the mitral valveannulus in a satisfactory manner for safe, stable and meticulousdeployment.

Further, unlike the aortic valve annulus which is entirely surrounded bymuscular tissue, the mitral valve annulus is bounded by muscular tissueon the outer wall only, with the inner side of the mitral valve annulusbeing bounded by a thin vessel wall which separates the mitral valveannulus and the aortic outflow tract. As a result, the mitral valveannulus cannot be subjected to any significant radial forces, as wouldbe typical with an expanding stent type of valve prosthesis, as suchradial forces would tend to collapse the aortic outflow tract, resultingin circulatory collapse with likely fatal consequences. As a result ofthese difficulties, firm anchoring of a deployed mitral valve prosthesisis currently not readily obtainable.

Mitral valve replacement techniques have also generally advocatedremoval of the native valve prior to location of the replacement mitralvalve prosthesis. This is a technically extremely challenging taskassociated with the potentially fatal complication of profound mitralregurgitation that may not be adequately addressed by the subsequentvalve replacement. The lack of an effective mitral valve may lead tooverwhelming hemodynamic instability that may not be tolerated by thealready compromised left ventricle and overwhelming pulmonary edema mayrapidly result.

OBJECT OF THE INVENTION

It is the object of the present invention to overcome or substantiallyameliorate at least one of the above disadvantages.

SUMMARY OF THE INVENTION

There is disclosed herein a percutaneous heart valve prosthesiscomprising:

a valve body having a valve body first end, a valve body second end anda passage extending along a longitudinal axis between said valve bodyfirst end and said valve body second end, said valve body beingcollapsible about said longitudinal axis for delivery via catheter;

one or more flexible valve elements secured to said valve body andextending across said passage for blocking bloodflow in one directionthrough said passage;

an anchor device, said anchor device being collapsible for delivery viacatheter; and

an anchor line secured to and extending between said valve body and saidanchor device.

The anchor device may comprise a collapsible anchor frame formed ofelongate elastic anchor frame elements. The anchor frame may becollapsible from a stable substantially flat plate-like configuration toan unstable elongate configuration for location within a catheter. Theanchor frame elements may each be formed of a superelastic shape memorymaterial.

The valve body may comprise a collapsible valve body frame formed ofelongate elastic valve body elements. The valve body frame elements mayeach be formed of a superelastic shape memory material.

The valve body typically tapers toward said valve body first end. Theanchor line is then usually secured to said valve body first end.

The valve body frame may comprise at least three valve body sub-framemembers, each said valve body sub-frame member having the general formof a deltoid, each said deltoid having acute-angled vertices at saidvalve body first and second ends, and oblique-angled vertices locatedbetween said valve body first and second ends. Each valve body sub-framemember may have the general form of a rhombus.

The valve body sub-frame members may be joined at respective saidoblique-angled vertices.

Each sub-frame member may further comprise a collapsible diagonalelement extending between said oblique-angled vertices. The one or morevalve elements is/are generally secured to the diagonal elements.

The valve body frame may alternatively be in the general form of acollapsible cylindrical ring.

The prosthesis may further comprise a plurality of prongs spaced about aperiphery of said valve body for engaging the native wall of a valveorifice in use.

The prosthesis may still further comprise a flexible skirt extendingabout a periphery of said valve body for blocking blood flow in said onedirection between said valve body and the native wall of a valve orificein use. Said flexible skirt may be formed of biological material,typically pericardial material.

The prosthesis is typically a mitral valve prosthesis.

There is further disclosed herein a percutaneous heart valve replacementsystem comprising:

a catheter having a catheter first end and a catheter second end;

a prosthesis as defined above located in said catheter, said valve bodybeing in a collapsed state and located towards said catheter first end,said anchor device being in a collapsed state and located between saidvalve body and said catheter second end; and

an elongate guide element having a guide element first end and a guideelement second end, said guide element first end being detachablyattached to said anchor device and said guide element second endextending beyond said catheter second end.

There is further disclosed herein a method of treating a failed orfailing mitral valve comprising the steps of:

advancing a first end of a catheter through the venous system of apatient to be treated into the right atrium of the patient's heart;

creating a puncture in the inter-atrial septum of the heart;

advancing said catheter first end through said puncture, into the leftatrium, through the native mitral valve and into the left ventricle ofthe heart;

locating a prosthesis as defined above in said catheter with said valvebody and said anchor device in a collapsed state, said valve body beinglocated between said anchor device and said catheter first end;

advancing said prosthesis through said catheter until said valve body isreleased from said catheter first end, thereby expanding said valve bodyfrom said collapsed state;

withdrawing said catheter first end through the mitral valve into theleft atrium;

withdrawing said valve body toward the left atrium, locating said valvebody in the orifice of the native mitral valve;

withdrawing said catheter first end through said puncture and into saidright atrium;

advancing said anchor device through said catheter until said anchordevice is released from said catheter first end, thereby expanding saidanchor device from said collapsed state;

engaging said anchor device with said inter-atrial septum about saidpuncture; and

withdrawing said catheter from the patient.

There is yet further disclosed herein a percutaneous heart valveprosthesis comprising:

a valve body having a valve body first end, a valve body second end anda passage extending along a longitudinal axis between said valve bodyfirst end and said valve body second end, said valve being collapsibleabout said longitudinal axis for delivery via catheter;

one or more flexible valve elements secured to said valve body andextending across said passage for blocking bloodflow in one directionthrough said passage;

wherein said valve body tapers toward said valve body first end, saidvalve body first end being sized to pass through a valve orificeassociated with a heart valve to be replaced, said valve body second endbeing sized so as not to pass through the valve orifice.

The valve body may comprise a collapsible valve body frame formed ofelongate elastic valve body elements. The valve body frame elements mayeach be formed of a superelastic shape memory material.

The valve body frame may comprise at least three valve body sub-framemembers, each said valve body sub-frame member having the general formof a deltoid, each said deltoid having acute-angled vertices at saidvalve body first and second ends, and oblique-angled vertices locatedbetween said valve body first and second ends. Each valve body sub-framemember may have the general form of a rhombus.

The valve body sub-frame members may be joined at respective saidoblique-angled vertices.

Each sub-frame member may further comprise a collapsible diagonalelement extending between said oblique-angled vertices. The one or morevalve elements is/are generally secured to said diagonal elements.

The prosthesis is typically a mitral valve prosthesis.

There is yet further disclosed herein a percutaneous heart valvereplacement system comprising:

a catheter having a catheter first end and a catheter second end;

a prosthesis as defined above located in said catheter, said valve bodybeing in a collapsed state and located towards said catheter first end;and

an elongate guide element having a guide element first end and a guideelement second end, said guide element first end being detachablyattached to said prosthesis and said guide element second end extendingbeyond said catheter second end.

There is further disclosed herein a method of treating a failed orfailing heart valve comprising the steps of:

advancing a first end of a catheter through the venous system of apatient to be treated into the right atrium of the patient's heart;

creating a puncture in the inter-atrial septum of the heart;

advancing said catheter first end through said puncture, into the leftatrium, through the native mitral valve and into the left ventricle ofthe heart;

locating a prosthesis as defined above in said catheter with said valvebody in a collapsed state and said valve body second end located betweensaid valve body first end and said catheter first end;

advancing said prosthesis through said catheter until said valve body isreleased from said catheter first end, thereby expanding said valve bodyfrom said collapsed state;

withdrawing said catheter first end through the mitral valve into theleft atrium;

withdrawing said valve body toward the left atrium, wedging said valvebody in the orifice of the native mitral valve; and

withdrawing said catheter from the patient.

There is still further disclosed herein a percutaneous heart valveprosthesis comprising:

a valve body having a valve body first end, a valve body second end anda passage extending along a longitudinal axis between said valve bodyfirst end and said valve body second end, said valve body beingcollapsible about said longitudinal axis for delivery via catheter;

one or more flexible valve elements secured to said valve body andextending across said passage for blocking bloodflow in one directionthrough said passage;

a flexible skirt extending about a periphery of said valve body forblocking bloodflow in said one direction between said valve body and thenative wall of a valve orifice in use.

The flexible skirt may be formed of biological material, typicallypericardial material.

The prosthesis is typically a mitral valve prosthesis.

There is still further disclosed herein a percutaneous heart valvereplacement system comprising:

a catheter having a catheter first end and a catheter second end;

a prosthesis as defined above located in said catheter, said valve bodybeing in a collapsed state and located towards said catheter first end;and

an elongate guide element having a guide element first end and a guideelement second end, said guide element first end being detachablyattached to said prosthesis and said guide element second end extendingbeyond said catheter second end.

There is further disclosed herein a method of treating a failed orfailing mitral valve comprising the steps of:

advancing a first end of a catheter through the venous system of apatient to be treated into the right atrium of the patient's heart;

creating a puncture in the inter-atrial septum of the heart;

advancing said catheter first end through said puncture, into the leftatrium, through the native mitral valve and into the left ventricle ofthe heart;

locating a prosthesis as defined above in said catheter with said valvebody in a collapsed state;

advancing said prosthesis through said catheter until said valve body isreleased from said catheter first end, thereby expanding said valve bodyfrom said collapsed state;

withdrawing said catheter first end through the mitral valve into theleft atrium;

withdrawing said valve body toward the left atrium, locating said valvebody in the orifice of the native mitral valve with said skirt locatedtoward the left ventricle; and

withdrawing said catheter from the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described by way ofexample with reference to the accompanying drawings, wherein:

FIG. 1 is a front elevation view of a percutaneous mitral valveprosthesis.

FIG. 2 is a front elevation view of a sub-frame member of the valve bodyof the prosthesis of FIG. 1 .

FIG. 3 is a schematic cross sectional front elevation view of the valvebody of the prosthesis of FIG. 1 .

FIG. 4 is a front elevation view of the valve body of the prosthesis ofFIG. 1 in a collapsed state located in a catheter.

FIG. 5 is a front elevation view of an alternate valve body of apercutaneous mitral valve prosthesis.

FIG. 6 is a front elevation view of the anchor device of the prosthesisof FIG. 1 .

FIG. 7 is a plan view of the anchor device of FIG. 6 .

FIG. 8 is a front elevation view of the anchor device of FIG. 6 in acollapsed state located in a catheter.

FIG. 9 is a schematic front elevation view of a patient depicting aguide wire accessing the patient's heart.

FIG. 10 is a schematic cross-sectional front elevation view of a heartdepicting a catheter advanced into the right atrium and a punctureformed in the inter-atrial septum.

FIG. 11 is a cross-sectional front elevation view of the heart of FIG.10 with the catheter advanced into the left ventricle.

FIG. 12 is a schematic cross-sectional front elevation view of the heartof FIG. 10 with a percutaneous heart valve prosthesis advanced throughthe catheter.

FIG. 13 is a schematic cross-sectional front elevation view of the heartof FIG. 10 with the valve body of the prosthesis released from thecatheter into the left ventricle.

FIG. 14 is a front elevation view of the heart of FIG. 10 with thecatheter withdrawn into the right atrium and the prosthesis valve bodylocated in the mitral valve orifice.

FIG. 15 is a schematic cross-sectional elevation view of the heart ofFIG. 10 with the prosthesis fully deployed.

FIG. 16 is a front elevation view of an alternative percutaneous heartvalve prosthesis.

FIG. 17 is a further view of the prosthesis of FIG. 16 .

FIG. 18 is a front elevation view of the prosthesis of FIG. 16 in acollapsed state located in a catheter.

FIG. 19 is a schematic cross-sectional front elevation view of a heartwith a partially deployed prosthesis of FIG. 16 .

FIG. 20 is a schematic cross-sectional front elevation view of the heartof FIG. 19 with the prosthesis fully deployed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring specifically to FIG. 1 , a percutaneous heart valveprosthesis, in the form of a mitral valve prosthesis 1, comprises avalve body 2, first and second flexible valve elements 3, 4, an anchordevice 5 and an anchor line 6 secured to and extending between the valvebody 2 and the anchor device 5.

The valve body 2 has a first end 7 and a second end 8. A blood flowpassage 9 extends along a longitudinal axis 10 between the valve bodyfirst end 7 and the valve body second end 8. The valve body 2 isconfigured so as to be collapsible about the longitudinal axis 10 toenable the valve body 2 to be located in a catheter for delivery of theprosthesis 1, as will be discussed further below.

The valve 2 is in the form of a collapsible valve body frame formed ofelongate elastic valve body frame elements 11. Each of the valve bodyframe elements 11 may be suitably formed as wires of a superelasticshape memory material. A particularly suitable material is nitinol, anickel-titanium alloy, which is known for use in percutaneous prosthesisapplications. Other suitable elastic metallic materials includestainless steel, gold, other titanium alloys and cobalt chromiummolybdenum. Other suitably rigid yet elastic metal alloys, ornon-metallic materials, may also be utilized as desired. The valve bodyframe elements 11 will typically have a thickness of the order of 0.3 to0.4 mm, however elements of varying diameter are also envisaged.

The valve body frame 2 depicted in FIG. 1 comprises three valve bodysub-frame members 12. One such valve body sub-frame member 12 isdepicted in FIG. 2 . As can best be seen from FIG. 2 , each valve bodysub-frame member 12 is in the general form of a deltoid, and hereparticularly in the form of a diamond or rhombus (that is, a deltoidwith four equal length sides). Each valve body sub-frame member 12 isarranged such that the acute-angled vertices 13, 14 of the rhombus arearranged at the valve body first and second ends 7, 8, with theoblique-angled vertices 15, 16 located between the valve body first andsecond ends 7, 8.

Each valve body sub-frame member 12 will generally be formed of twowires, kinked to form the oblique-angled vertices 15, 16, with the endsof each wire being soldered to form the acute-angled vertices 13, 14,thereby providing the rhombus form.

Alternatively, the wires could be kinked to form the acute-angledvertices 13, 14, with the ends soldered at the oblique-angled vertices15, 16.

Adjacent valve body sub-frame members 12 are joined at their respectiveoblique-angled vertices 15, 16 as depicted in FIG. 1 , typically bysoldering. Alternatively, the adjacent valve body sub-frame members maybe sutured or joined by any other suitable means. Whilst, in the valvebody 2 depicted, three sub-frame members 12 are joined so as to providea generally triangular transverse cross-section, more than threesub-frame members may be utilized as desired such that the transversecross-section of the valve body 2 becomes gradually more circular inshape with the addition of further body sub-frame members 12.

As is particularly apparent from FIG. 1 , the valve body 2 is arrangedsuch that it tapers towards the valve body first end 7. The valve bodyis tapered and sized such that the valve body first end 7 is able topass through a mitral valve orifice associated with a mitral valve to bereplaced, with the valve body second end 8 being sized so as not to passthrough such a mitral valve orifice, when in the uncollapsed state. Amitral valve orifice in an adult person typically has a diameter of theorder of 25 mm.

Referring again particularly to FIG. 2 , each valve body sub-framemember 12 may further comprise a collapsible diagonal element 17extending between the oblique-angled vertices 15, 16. The diagonalelements will typically be in the form of a kinked wire formed of thesame material as the remaining elements 11 of the valve body sub-framemember 12. The kink is provided in the diagonal element 17 to enable itto readily collapse to allow delivery via catheter.

Referring to FIGS. 1 and 3 , the valve elements 3, 4, in the form ofvalve leaflets, are secured to the valve body 2 on opposing sides of thebloodflow passage 9. Typically, the valve leaflets 3, 4 will be suturedto the diagonal elements 17 of the valve body sub-frame members 12. Thevalve leaflets 3, 4 are here overlapping, typically with a shorterleaflet 3 overlapped by a longer leaflet 4 lying between the shorterleaflet 3 and the valve body second end 8, such that, in use, the longerleaflet 4 lies on the outer or ventricular side of the valve body 2.Referring to FIG. 3 , it can be seen that sub-frame members 12 areplanar.

The valve leaflets 3, 4 are configured in a known manner so as to opentoward the valve body second end 8, allowing bloodflow through thepassage 9 in a direction from the valve body first end 7 toward thevalve body second end 8, and to sealingly lock in response to pressureacting in the opposite direction, so as to block bloodflow through thepassage 9 in the reverse or retrograde direction. The valve leaflets maybe formed of biological material, such as pericardial material, as iswell known in the art, or of any other suitable flexible valve materialsknown in the art, including woven metallic materials or non-metallicmaterials such as silicone. The valve leaflets may be sutured to thediagonal element 17 around the entire periphery of the passage 9, or maybe hinged only at one or more discrete points around the periphery ofthe passage 9. Any of various well known valve leaflet configurationsmay be utilized so as to provide the one way valve function required,including configurations utilizing one valve leaflet only or utilizingthree or more valve leaflets as is known in the art. Alternatively, asingle valve element in the general form of a windsock might beutilized.

Referring to FIG. 4 , the configuration of the valve body 2 facilitatesit being collapsed about the longitudinal axis 10, enabling it to fitwithin a catheter 18 for subsequent percutaneous deployment.

As depicted in FIGS. 1 and 2 , prongs, typically in the form of barbs19, may be spaced about the periphery of the valve body 2, typically ator adjacent the oblique-angled vertices 15, 16 of each sub-frameelement, for engaging the native annular wall surrounding a valveorifice in use, as will be discussed below. Further barbs may be locatedat the acute-angled vertices 24 at the valve body second end 8. Thebarbs 19 will typically point toward the end 7, when the anchor line 6is secured to the valve body first end 7.

Referring to FIG. 5 , a flexible skirt 20 may extend around theperiphery of the valve body 2 for blocking retrograde bloodflow towardthe valve body first end 7, between the valve body 2 and the native wallsurrounding the mitral orifice in use. The flexible skirt 20 willtypically be sutured to the diagonal element 17 of each valve bodysub-frame member 12, and as such will effectively provide a continuationof the valve leaflets 3, 4 on the exterior of the valve body 2. Theflexible skirt 20 may be formed of biological material, such aspericardial material, or alternatively might be formed of any suitableflexible non-biologic material, such as, for example, silicone,polyester or dacron.

Referring to FIG. 6 , the anchor device 5 will also typically comprise acollapsible anchor frame formed of elongate anchor frame elements 21.The anchor frame elements 21 will again typically be formed of asuperelastic shape memory material as per the valve body elements 11,and may again be formed of nitinol or other suitable elastic materials.Here the anchor device frame 5 is formed of an array of anchor sub-framemembers 22. Each anchor sub-frame member has the general form of arhombus. Rather than being joined side to side as per the valve bodysub-frame members 12, however, the anchor sub-frame members 22 are hereeach joined in a radial pattern at their oblique-angled vertices 23, 24.

Accordingly, the anchor device 5 is collapsible from a stablesubstantially flat plate-like configuration (as depicted in FIGS. 6 and7 ) to an unstable elongate configuration for location within a catheter18 (as particularly depicted in FIG. 8 ). The anchor device 5 isprovided at one end, corresponding to the oblique-angled vertices 23,with a coupling 25 for releasably coupling to a guide element as will bediscussed below. The coupling 25 may suitably be in the form of athreaded aperture.

The anchor line 6 will also generally be secured to the end of theanchor device 5 corresponding to the oblique-angled vertices 23, andwill extend through the length of the anchor device 5 beyond theopposing oblique-angled vertices 24, such that tension applied to theanchor line 6 will tend to retain the anchor device 5 in the flatconfiguration. The anchor line 6 may be formed of any suitable flexiblewire or cord, and may be suitably formed again of nitinol wire orstainless steel wire. Other suitable materials may include carbon fiber,polyimides or aromatic polyamides. Where elasticity in the anchor lineis desired, other suitable materials may include polyether block amide(PEBAX), silicone or polyurethane.

The opposing end of the anchor line 6 will typically be secured to thevalve body first end 7, typically by way of three further lines 6 aconverging from the acute angled-vertices 13 of each-frame member 12 ofthe valve body 2. Where desired, further anchor lines 6 extendingbetween the valve body 2 and anchor device 5 may be utilized.

The structure of the valve body 1 and anchor device 5 may be coveredwith biological material or less thrombogenic material to reduce thepossibility of blood clotting around the non-biological material fromwhich the valve body 2 and anchor device 5 will typically be formed.

A surgical procedure for replacement of a native mitral valve 101utilizing the prosthesis 1 will now be described with reference to FIGS.9 to 15 . Given that the native mitral valve 101 and mitral valveorifice 102 will generally vary in size between patients, measurementsof the native mitral valve 101 and orifice 102 may be made with the useof a compliant balloon and transthoracic and transesophagealechocardiography.

The compliant balloon is located in the valve orifice 102 and expandedso as to move the leaflets of the native valve 101 out of the way andenable measurement of the diameter of the mitral valve orifice 102. Ameasurement of the distance between the native mitral valve 101 and theregion of the inter-atrial septum 103 is also taken.

Based on the measurements taken, a suitably sized prosthesis valve body2 is selected to fit the size of the mitral valve orifice 102 such thatthe valve leaflets 3, 4, will be positioned in the vicinity of thenative valve 101. The measurement of the distance between the nativemitral valve 101 and the mid region of the inter-atrial septum 103 isalso utilized to determine the length of the anchor line 6 extendingbetween the valve body 2 and anchor device 5, such that the anchor line6 will be taught when the prosthesis 1 is deployed, as will be discussedfurther below.

The venous system of the patient to be treated is accessed via apuncture 104, typically in the groin area, accessing the femoral vein105. Access to the venous system might alternatively be made via otherlarge peripheral veins such as the subclavian or jugular veins. Thefemoral vein 105 is, however, preferred given the compressibility of thefemoral vein 105 once a catheter is removed from the patient to achievehaemostasis.

A guide wire 26, typically having a diameter of approximately 0.85 to1.7 mm, is then inserted through the puncture 104 and along the femoralvein 105 and via the inferior vena cava 106 to the right atrium 107 ofthe patient's heart 100 as depicted in FIG. 9 . If additional steadyingof the guide wire 26 is desired, a snare may be introduced to the heart100 through an arterial approach from the left or right femoral artery,aorta and aortic valve. The snare will then engage a J-tip on the end ofthe guide wire 26 and draw the end of the guide wire 26 through thearterial system to the exterior of the patient so that opposing ends ofthe guide wire 26 may be steadied.

A catheter 18, typically having an internal diameter of at least 8French (approximately 2.8 mm) is then advanced over the guide wire 26and into the right atrium 107. Referring to FIG. 10 , a puncture 108 isthen made in the inter-atrial septum 103 using conventional equipmentadvanced via the catheter 18 in the known manner. The guide wire 26 andcatheter 18 are then further advanced through the septal puncture 108into the left atrium 109, through the native mitral valve 101 and intothe left ventricle 110 as shown in FIG. 11 . The first end 27 of thecatheter 18 is thus located in the left ventricle 110 whilst theopposing second end of the catheter 18 is still located on the exteriorof the patient.

The mitral valve prosthesis 1 is then collapsed and fed into the secondend of the catheter 18, with the second end 8 of the collapsed valvebody 2 leading. An elongate prosthesis guide element 29 is detachablyattached to the prosthesis 1, here by way of the screw threaded coupling25 of the anchor device 5. The prosthesis guide element 29 may be afurther guide wire with a cooperating screw threaded coupling 30 on itsend, or alternatively might be a narrower catheter. The prosthesis 1 isadvanced along the catheter 18 toward the catheter first end 27 as shownin FIG. 12 . Rather than using a screw threaded coupling arrangement 25,30 to couple the anchor device 25 and prosthesis guide element 29, aclip, clamp or the like may be utilized.

The prosthesis 1 is advanced until the valve body 1 is released past thecatheter first end 27 and into the left ventricle 110 as shown in FIG.13 . As the valve body 2 is released from the catheter first end 27, theelasticity of the valve body frame results in the valve body 2 extendingto its uncollapsed state. The valve body 2 remains attached to theanchor device 5 by way of the anchor line 6.

Referring to FIG. 14 , the catheter 18 is then withdrawn through thepuncture 108 such that the catheter first end 27 is located in the rightatrium 107. Simultaneously, the prosthesis guide element 29 is withdrawnso as to draw the expanded valve body 2 toward the native mitral valveorifice 102 and left atrium 109. As the valve body first end 7 is sizedto enable it to pass through the mitral valve orifice 102, and the valvebody 2 is tapered such that the valve body second end 8 is sized so asnot to pass through the mitral valve orifice 102, the valve body 2engages the annular wall 111 of the mitral valve orifice and thusbecomes wedged within the valve orifice 102. The valve body diagonalelements 17 and valve leaflets 3, 4 are ideally positioned adjacent thenative mitral valve 101, whose leaflets are pushed away and crushedagainst the mitral valve orifice wall 111 by the valve body 2.Accordingly, with the native mitral valve 101 being pushed away from themitral valve orifice 102, there is no need to remove the native mitralvalve 101.

The barbs 19 protruding from the valve body 2 and facing towards thevalve body first end 7 (and thus the left atrium 109) pierce into thevalve orifice wall 111 as the valve body 2 is wedged into position. Thebarbs 19 located adjacent the valve leaflets 3, 4 engage the valveorifice wall 111 in the vicinity of the native valve leaflets, whilstthe barbs 19 at the valve body second end 8 engage additional cardiacstructure surrounding the lower end of the valve orifice 102 within theleft ventricle 110.

The peripheral skirt 20 extending about the valve body 2 is located onthe ventricular side of the mitral valve orifice 102, so as to sealbetween the periphery of the valve body 2 and the mitral valve orificewall 111 when the left ventricle 110 contracts and pressurises duringventricular systole.

The catheter 18 is then further retracted such that the anchor device 5is released from the catheter first end 27. As the anchor device 5 isreleased it expands to its un-collapsed state and, with appropriatesizing of the anchor line 6, engages the inter-atrial septum 103 fromwithin the right atrium 107, as shown in FIG. 15 . The catheter 18 andguide wire 26 are then drawn back through the venous system and removedfrom the patient to complete the procedure. At any stage during thedeployment process, the anchor device 5 and valve body 2 may beretracted back into the catheter 18 and removed if any difficulties areencountered.

The anchor device 5 thus securely anchors the valve body 2 in the mitralvalve orifice 102 against migration towards the left ventricle 110during atrial systole, when the left atrium 109 contracts andpressurizes. The tapered configuration of the valve body 2, effectivelywedging the valve body 2 into the mitral valve orifice 102, anchors thevalve body 2 against migration towards the left atrium 109 duringventricular systole. The barbs 19 additionally anchor the valve body 2against migration towards the left atrium 109.

Once the prosthesis is successfully in place, the prosthesis guideelement 29 is detached from the anchor device 5, by rotating theprosthesis guide element 29 to thereby decouple the threaded coupling.

The entire procedure may be performed under the guidance of fluoroscopy,transthoracic and transesophageal echocardiography in a known manner.

The valve leaflets 3, 4 replace the function of the native mitral valveleaflets, allowing bloodflow from the left atrium 109 to the leftventricle 110 through the mitral valve orifice 102 and bloodflow passage9 of the valve body 2 during atrial systole, whilst blocking retrogradeflow from the left ventricle 110 to the left atrium 109 duringventricular systole. The peripheral skirt 20 further blocks bloodflowthrough any gaps between the valve body 2 and the mitral valve orificewall 111 in the retrograde direction during ventricular systole.

In addition to, or in place of, the barbs 19 and tapered shape of thevalve body 2 anchoring the valve body 2 against migration towards theleft atrium 109, a further anchor device 5 might be utilized to anchorthe valve body 2 to the inter-ventricular septum 112. Similarly, thetapered form of the valve body 2 might be utilized in conjunction withother mechanisms for securing the valve body 2 against migration towardsthe left ventricle rather than utilizing the anchor device. It isfurther envisaged that the general valve prosthesis configuration may beutilized for other types of heart valve prosthesis, for replacement ofthe aortic semiluminar valve, pulmonary semiluminar valve or tricuspidvalve, utilizing alternative structures of the heart for securing theanchor device.

An alternate form of valve prosthesis 201 is depicted in FIGS. 16 to 20. The prosthesis 201 has an anchor device 5 much the same as that of theprosthesis 1 of FIG. 1 , however the valve body 202 is in the generalform of a collapsible cylindrical ring. The collapsible ring 202 isformed of a squat cylinder and may have a woven construction formed ofelongate elastic elements, typically metallic wire. Again, aparticularly suitable material is a superelastic shape memory materialsuch as nitinol. The valve body ring 202 should be sized so as to havean undeformed diameter slightly larger than that of the mitral valveorifice 102, such that when deployed, a compressive force is applied tothe wall 111 of the valve orifice 102 to assist retaining the valve bodyin place. Care should be taken, however, not to oversize the valve bodyring 202 such that an excessive compressive force is applied to themitral valve orifice wall 111 which, as discussed above, may result incollapsing of the aortic outflow tract.

The valve body ring 202 is arranged such that it may be collapsed into acylindrical shape of reduced diameter, enabling it to be loaded into acatheter 18, as depicted in FIG. 18 in a similar manner to the valvebody 2 described above.

Valve leaflets 3, 4, as described above in relation to the firstprosthesis 1, are secured to the valve body ring 202, again typically bysuturing. Here three anchor lines 6 secure the valve body ring 202 tothe anchoring device 5, with the anchor line 6 being secured at pointsspaced equidistantly about the valve body ring 202.

Prongs 19 protrude from the valve body ring 202 toward the anchoringdevice 5 for engaging the valve orifice wall 111 in much the same manneras discussed above.

Referring to FIGS. 19 and 20 , deployment of the prosthesis 201 isgenerally the same as that described above in relation to the firstprosthesis 1, with the primary difference being the lack of a taperedbody that is wedged into the mitral valve orifice 102 to assistanchoring against migration towards the left atrium 109. The valve bodyring 202 thus relies on the barbs 19 and compressive force applied tothe mitral valve orifice wall 111 to prevent migration towards the leftatrium 109.

What is claimed is:
 1. A method of replacing the function of aregurgitant native heart valve, comprising: advancing a catheter througha venous system and into a right atrium of a heart, the catheter havinga valve prosthesis disposed along a distal end portion thereof, thevalve prosthesis comprising: a valve body comprising a collapsible framemade from a shape memory material, the valve body having a first end, asecond end, a longitudinal axis, and a blood flow passage extendingalong the longitudinal axis between the first end and the second end,the valve body have an undeformed diameter sized to be larger than anorifice of the native heart valve, the valve body being collapsibleabout the longitudinal axis for placement within the catheter; aflexible skirt made from polyester, the flexible skirt sutured to thecollapsible frame, the flexible skirt dimensioned for blocking bloodflow through a space between the collapsible frame and the orifice ofthe native heart valve; a one-way valve positioned within the blood flowpassage and sutured to the collapsible frame, the one-way valve adaptedfor permitting blood to flow from the first end of the valve body to thesecond end of the valve body, the one-way valve formed by three flexiblevalve leaflets made from a pericardial material; and a plurality ofprongs spaced about the periphery of the valve body, wherein each prongpoints toward the first end of the valve body; releasing the valveprosthesis from the catheter; and allowing the valve prosthesis toradially expand within the orifice of the native heart valve, wherein aforce is applied to the orifice of the native heart valve by the valveprosthesis and wherein the prongs engage surrounding tissue forpreventing migration of the valve prosthesis towards an atrium of theheart, wherein the valve body is formed by a plurality of sub-framemembers, each sub-frame member having a general form of a rhombus withacute-angled vertices and oblique-angled vertices.
 2. The method ofclaim 1, wherein the native heart valve is a mitral valve.
 3. The methodof claim 2, wherein the catheter is advanced into a right atrium andthrough a puncture formed in the inter-atrial septum.
 4. The method ofclaim 1, further comprising an anchoring member secured to the first endof the valve body.
 5. The method of claim 4, wherein the anchoringmember comprises a radially expandable anchor device.
 6. The method ofclaim 5, wherein the anchoring member further comprises an anchor lineextending between the valve body and the anchor device.
 7. The method ofclaim 1, wherein the native heart valve is a tricuspid valve.